This type of Luer-Lock connector is known from DE 103 03 381 A1. This Luer-Lock connector, as is also generally common in medical technology, has a tubular body and a swivel nut with an inside thread secured on it and enclosing it, which thread engages in the outside thread of a Luer-Lock mating element. Ordinarily the swivel nut is applied to the so-called male Luer-Lock part. During assembly, it is pushed on from the free end of the tubular body and is necessarily widened a certain degree in so doing. Even if one remains fully within the elastic range, the swivel nut, after assembly, can be pushed down again by corresponding expansion, so that an unreleasable fastening of the swivel nut is scarcely possible after being pushed on.
In order to avoid sliding down of the swivel nut during tensile stress, as occurs during tightening, an edge is applied to the swivel nut and the tubular body, the two edges serving as a stop against pulling down. Such edges can secure the swivel nut relatively well in practice. However, if the material is plastically expanded during pushing-on of the swivel nut, this edge cannot guarantee secure fastening of the swivel nut. Another drawback of such an edge is that the swivel nut can be arbitrarily rotated farther, since it is not pulled into a cone that would lead to locking or fastening of the swivel nut. During further rotation of the swivel nut, the female Luer connector is invariably pulled onto the male Luer cone. Because of this, significant stresses develop in the female Luer connector, which can rapidly lead to material failure, like stress cracks or leaks. Another drawback of an edge is that, with insufficient fastening of the swivel nut or unduly smooth surfaces of the threads, there is a hazard that the swivel nut will automatically rotate back and the entire connection will loosen. This is further promoted by lubricants or liquids.
In DE 103 03 381 A1, a cone is present between the swivel nut and the male Luer cone, which causes widening during pushing-on of the swivel nut, and especially of its radially inward-protruding edge, and therefore increases the risk that the swivel nut can be pulled from the tubular body.
A Luer-Lock connector, in which two parts, rotatable relative to each other, can be fastened to each other by stop edges in the axial direction, is also known from U.S. Pat. No. 6,364,869 B1. Here again, however, a slope is provided, which can cause widening of the outer part during pushing-together of the parts.